Room: AAPM ePoster Library
Purpose: This study was to retrospectively evaluate and compare lung cancer SBRT plans which were generated for Varian Truebeam equipped with 2.5 mm width multileaf collimator (MLC) and Varian Vitalbeam with 5.0 mm width MLC.
Methods: Same patients were selected for both linear accelerators. Existing structure sets (for Truebeam) including same PTV volume ranging from 20 cc to 50 cc were used to replan for Vitalbeam. Optimization and dose calculation were performed using the same beam configurations, calculation algorithm and resolution.
Results: Dosimetric characteristics of treatment plans for Vitalbeam were similar to those on Truebeam. Slightly better target volume coverage and lower maximum dose were observed in Vitalbeam plans with thicker MLC, while conformity and gradient index showed marginally larger values compared to Truebeam.
Conclusion: The results showed no significant difference on dosimetric parameters for both thinner and thicker MLC sizes (2.5 mm and 5 mm) if lung lesions were larger than 3 cm in diameter.